I have seen the loading bar since the first beta, one thing I did notice though is initially in the beta I would see the loading bar before I would see my login. Now after reformatting and updating to the official OS (with encryption enabled) I see the loading bar after I use my password. It doesn't last very long fortunately.

Back to the Future? Memories of past OSs.
Perhaps there were old school Macoyltes who complained that with no loading bar, they couldn't tell if their Mac was booting or had frozen - even if, on the MBA, the boot means only waiting 20 second to find out.

Speaking of which..... My iMac set at the login screen for a while and then it said something about opening where it left off. I hit cancel and it loaded my account without needing my password! That scares me. Terrible security flaw.